FIG. 1 is a partially sectional side view illustrating an example of miniature motors to which this invention is applied. In FIG. 1, reference numeral 31 refers to a case formed of a metallic material, such as mild steel, into a bottomed hollow cylindrical shape, to the inner circumferential surface of which a permanent magnet of an arc-segment shape, for example, is fixedly fitted. Numeral 33 refers to a case cover formed of a thermoplastic resin material in such a manner as to fit to the opening of the case 31. Numeral 34 refers to a rotor consisting of an armature 35 facing the permanent magnet 32, and a commutator 36, and rotatably supported by bearings 37 and 38 each provided on the case 31 and the case cover 33.
Numeral 39 refers to a brush arm formed of an electrically conductive material into a strip shape, having a brush 40 for making sliding contact with the commutator 36, and provided in the case cover 33. In the case cover 33, also provided is an input terminal 41 for electrically connecting the brush arm 39 so that power can be fed from an external d-c source to the armature 35 via the brush arms 39, the brushes 40 and the commutator 36.
As current is fed to the armature 35 of a miniature motor of the above-mentioned construction, rotating force is generated in the armature 35 existing in a magnetic field formed by the permanent magnet 32 fixedly fitted to the inner circumferential surface of the case 31, and thus the rotor 34, and various equipment connected to the rotor 34 are caused to rotate.
In the miniature motor as described above, a capacitor, as shown in FIGS. 2 and 3, is usually installed to reduce electrical noise. In FIGS. 2 and 3, like parts are indicated by like numerals shown in FIG. 1. FIG. 2 shows an example in which a capacitor 42 is connected across input terminals 41 and 41 via lead wires 43. FIG. 3, on the other hand, shows an example in which capacitors 42 are installed on the inside surface of the case cover 33; one lead wire 43a of the capacitor 42 being connected to the input terminal 41, and the other lead wire 43b to a case 31 made of a metallic material.
The example shown in FIGS. 2 and 3, however, involve extremely complex and troublesome operations to connect the lead wires 43, 43a and 43b to the input terminal 41 or the case 31. That is, soldering operations associated with electrical connections, and operations of placing and cutting the lead wires 43, 43a and 43b require a certain degree of skill, leading to increased time and manhours, and to increased manufacturing cost accordingly. Furthermore, soldering in a limited space tends to make connections between members quite unstable, resulting in vulnerability to vibration, impact, etc. during service, and in inadequate reliability in terms of electrical connection.